The Macromolecular Structure Core Facility is comprised of three facilities-the X-ray crystallography (X-ray) facility, the high-field nuclear magnetic resonance (NMR) facility, and atomic force microscopy (AFM) facility. The Shared Resource is directed by Andrew P. Hinck, Ph.D., who has worked in the field of biomolecular Nuclear Magnetic Resonance (NMR) for 14 years. SACI investigators will be assisted in utilizing these state-of-the-art technologies to address structural determinations and problems of structure-function relationships between drug targets and potential therapeutic agents. X-ray crystallography, high field NMR, and AFM are highly complementary methods for elucidating three-dimensional structural information on biological macromolecules. Together, they provide SACI members with a comprehensive array of methodologies with which to visualize cancer-related biological macromolecules. The Atomic Force Microscopy Facility includes a Digital Instruments NanoScope IIIa microscope with two vertical engagement scanners. The types of molecules that can be studied by AFM include proteins and nucleic acids as single molecules or in complexes (sizes ranging from very large to down to a few nanometers), biological membranes, and surface characterization of cells and organelles (sizes up to 150 ms). The X-ray Crystallography Facility includes three complete X-ray data collection systems. The instrumentation provides full capabilities for conducting all modern X-ray diffraction experiments and is suitable for obtaining high quality three-dimensional structures of proteins, nucleic acids and their complexes. The High Field Nuclear Magnetic Resonance Facility is equipped with three state-of-the-art Bruker Avance NMR spectrometers operating at 500 (01/2000), 600 (08/2001), and 700 (01/2002) MHz. The NMR facility also supports an extensive network of off-line computer workstations and associated software to facilitate in the off-line processing and analysis data collected in the facility.